Centrifugal valve-casting machine



F. HILTY.

CENTRIFUGAL vALvE cAsnNG MACHINE.

APPLICATION FILED MAR-28. 1919- Patented Jan. 27, 1920.

3 SHEETS-SHEET l.

F. HILTY. CENTRIFUGAL vALyE CASTING MACHINE.'

APPLICATION FILED MAR. 28, 1919.

Patented Jan. 27,1920.

3 SHEETS-SHEET 2.

F. HILTY. CENTFIIFUGAL VALVE CASTING MACHINE.

APPLICATION FILED MAR-28. 1919.

UNTTED STATES PATENT onnron.y

FREDERICK HILTYOF WAUKEGAN, ILLINOIS, ASSIGNOR TOLAURENCE R. WILDER, OF CHICAGO, ILLINOIS.

CENTRIFUGAL VALVE-CASTING MACHINE.

Specication of Letters Patent.

Patented Jan. 27, 192e.

To all 'whom z't may concern.'

Be it known that-I, FREDERICK HILTY, a citizen of the United States, residing at Vaukegan, in the county of Lake and State of Illinois, have inventedv a ,certain new and useful Improvement in Centrifugal ValveC-asting Machinesyof which the following is a full, clear, cncise, and exact description, reference being had'to the accompanying drawings, forming ya part of thisspecification.

My invention relates to a-centrifugal casting machine, and more specicallyis concerned with the provision. of a y machine whereby to cast puppetvalves of the type commonly employed lin connection with internal combustion engines. g

Among its objects my invention contemplates:

First: The provision of a machine whereby the casting of valves may be accomplished cheaply and with a high degree of speed.

Second: To provide an apparatus for casting valves which require a minimum amount of machining to render them ready for use. e

Third: The provision of means for casting a valve the metal constituting which is of greatest density at 4the points where greatest density is required, to wit, in the head and at the point where the valve stem joins the head.

Fourth: A valve-casting apparatus so constructed and operated that when the valve is finally cast the impurities which happen to be in or get in the molten metal from any source are restricted to portions of the finished casting away from the points subjected to the greatest strain in the operation of the valve on an engine.

Fifth: A valve-casting device comprising simple and eiicient means which during the casting operation e'ectually prevents the metal constituting the valve stem from pulling away from the metal constituting the valve head, due to the shrinkage of the metal as it cools from a molten to a solid state.

Sixth: A machine comprisingmolds of novel construction which are efficient in use and which may readily and economically be prepared for use in the casting operation.

Other objects of my invention will appear as this description progresses.

In the accompanying drawings illustrating one embodiment of my invention Figure 1. is an elevational view of a machine embodying the improvements of my invention, ,the machine in this case being provided with two centrifugal casting units;

Fig. 2 is an elevational view of one of the rotors or mold holder cases and its contents, certain parts being illustrated in section more clearly to reveal the -construction thereof.

Fig. 8 is a sectional view taken on line 3-3 of Fig. 2 and looking in the direction indicated by the arrows;

Fig. 4 is a fragmentary sectional view taken on line H of Fig. 2;V

Fig. 5 is a fragmentary sectional view taken on line 5-5 of Fig. 2;

Fig. 6 is a fragmentary view in perspective of one-half of one of the annular4 mems1 bers which provide the annular pouring trough or channel and likewise provide the sprues for the several molds; and

Fig. 7 is a view in perspective of a valve casting as it comes from the casting machine.

Similar characters of reference refer to similar parts throughout the several views.

Referring first to Fig. 1, at 10 I have illustrated a machine frame of any suitable construction provided with suitable bearings 11, 11, in which is mounted a shaft 12 conveniently provided with a pulley 13, whereby the shaft 12 may be driven at the re- .quired speed from any available source of power. In the arrangement illustrated in Fig. 1 I have rovided each end of the shaft 12 with'w at may be termed a rotor or mold holder case 14. It will be understood that the rotor or mold holder cases, as well as Atheir contents, are identical, and that the use of two casting units in a single machine is a matter of choice, wherefore in the further description of my invention I shall confine myself to a description of one casting machine unit,-that is, I shall confine my description to one of the rotors 14 and its contents.

The rotor 1-1 in each case is conveniently provided with a hub pinned or othewise suitably secured upon the shaft 12, the .rotor moreover being desirably provided with a. plurality of strengthening ribs or webs 15, 15. The use of the ribs l5, 15, or any other expedient, to strengthen the rotor and render its use safe under the centrifugal stresses to which it is subjected is of course a matter of choice.

The rotor or mold holder case is designed to receive and carry a plurality of molds and mold holders which, when ready for use, are rigidly connected together and in effect constitute a unit which may .be readily inserted in or removed from the' rotor or mold holder case. The mold and mold holder unit just referred to comprises an ann-Lilus consisting of two rings 16, 16 provided with inwardly and outwardly extending radial flanges 17, 17 and 1'8, 18, It is to be noted that the opposing flanges 17, 17 of the rings 16, 16 are conformed to provide an annular recess for the reception of a two-piece annular core 19 which, it may be pointed out,

lprovides a groove or channel into which the molten metal is poured during the casting operation and from which the molten metal is forced by centrifugal force to the recesses in the several individual molds. The opposing flanges y18, 18 of the rings 16, 16 are secured together by a plurality of bolts, 20, 20.

v As is most clearly illustrated in Figs. 2

4 and 3, the opposing flanges 18, 18- of the rings 16, 16 are suitably conformed at 21, 21 for the ref'eption of the individual mold holders, each of which comprises two symmetrical sections 22, 22. It is to be noted that each of the individual mold holders extends radially from the axis of the rot-or or mold holder case, and that each mold holder consists of two of the mold holder sections 22, 22, each 0f which at its lower end is embraced by and is secured to the flange 18 of one of the rings 16. It is to be noted that I prefer that each of the individual mold holders shall in cross-section roughly approximate the cross-section of a ypuppet valve, but this arrangement, al-

though possessing a number of advantages, is by no means essential, yas I contemplate using mold holders of plain cylindrical cross-section, if desired.

The annular core 19, which is embraced within the inwardly extending radial flanges 17. 17 of the rings 16, 16, is conveniently formed in two parts, as is most clearly shown in Figs. 3, 4 and 5, the two parts of the core being conformed to provide on its inner periphery a substantially V-shaped channel 23, into which the molten metal is poured during the casting operation, I find it convenient to form the core 19 of molding sand bakedto give it the necessary strength, but I do not so limit myself, as I contemplate constructing the core 19 of any available material suitable' for the purpose for which it is intended. As is perhaps most clearly illustrated in Fig. 6, each half of `the annular core 19 is provided with a semi-circular depression 24 with which con- -Vshaped channel 23 to the sockets formed by, the depressions 24.

Each of the individual mold holders carries a one-piece mold 25, formed with a mold cavity corresponding to the stem and the underside and lateral surfaces of the head of a puppet valve such as are commonly used in connection with internal combustion engines. It will be understood that the inner end of the cavity in the one-piece mold 25 registers with one of the sprues formed in the annular core 19, whereby during the casting operation metal may be forced from the channel 28 into the cavity of mold 25 by centrifugal force, as will presently be explained. It-will be noted that the inner end of the mold 25 extends beyond the inner end of the mold holder by which it i's carried, and is received by one of the sockets in the outer periphery of the annular core 19. Itis to be understood that the one-piece mold 25 may, if desired, be made of molding sand formed and baked in a well-known manner, although I contemplate constructing the one-piece mold 25 of any suitable material.

As has been pointed out, the one-piece mold 25 is provided with acavity corresponding to the stem and the underside and lateral surfaces of the head of a puppet valve. Each of the individual mold holders is provided at26 with a plug or core, the inner surface of which is conformed to give the valve head as cast the desired conformation. In the drawings I have illustrated the core or plug 26 as conformed to give the valve head a concave upper surface, but it will be understood that theI core or plug 26 in each case may be conformed to correspond to a valve head having a flat, convex,

stood that the plugs or cores 26 may be formed of baked molding sand or any other suitable material. I prefer that each of the plugs or cores 26 lshall be provided with a 'metal member 27` which may b'e in the form of a steel nail, having its head embedded -in the plug or core and a shank extending from the inner surface thereof into the cavity `or other desirable form. 1t is to be underthe bolts 20, 20. With the structure thus separated, the two parts of the core 19 may be assembled as illustrated in the drawings, and the several one-piece mold members and their cooperating cores or plugs 26 may be placed in their several mold holders, as illustrated in the drawings. The rings 16, 16 are then secured together by the bolts 20, 20, and the core 19 .and mold parts held securelyin position, with the several sprues formed in the annular core 19 registering with the 'several cavities in the one-piece mold members 25, carried by the individual mold holders. For convenience in assembling Ivprefer to provide one of the rings 16 with a plurality of dowels 28 arranged to engage in suitable recesses in the other ring 16 when the said rings are assembled as shown in Fig. 4, in order that when assembled the flanges 18, 18 of the rings 16,

' 16 will be so disposed as properly to hold the sections 22,- 22 of each of the individual mold holders in proper position.

The entire structure carried by the rings 16, 16 may be retained within the rotor or mold holder case 10 by arms or brackets 29, 29, each of which is secured to the inner surface of the rotor or mold holder case and extends over one of the individual mold holders in the direction of rotation. Thus the entire inner structure comprising the several individual mold holders may be inserted in the rotor or mold holder case, and by being turned a few degrees in a direc'- tion opposite that in which the rotor is intended' to turn, the entire inner structure is retamed in position by brackets 29, 29.

Before proceeding to describe the operation of my improved casting machine, I will describe a convenient guard and pouring spout which may be used in connection with the centrifugal casting machine just described.

Referring now to Figs. 1 and 3, I have illustrated at 30 a three-wheel truck which carries a metal guard vin the form of a plate 31 provided with a central opening 32 arranged to lie opposite the V-shaped channel 23 of the core 19 when the guard is placed in the position illustrated in Figs. 1 and 3. The plate 31 is conveniently provided with a iiange 33 formed integrally therewith orA riveted thereto, as shown, which flange is arranged to extend over and around the periphery of the rotor or mold holder case 10 when the guard is in the position illustrated. The truck 30 and the guard plate 31 conveniently support a framework 34, carrying a plate 35 constituting a cradle for the rear end of a pouring spout 36. the nose portion of which extends through the aperture 32 of the guard plate 31, and is so Clisposed that molten metal, when poured into the spout, will flow directly into the V- shaped channel :Z3 of the annular core 19 of the'casting device. The spout is held in position by a bracket 37 which is secured to the umlersurface of the pouring spout, and which abuts against the plate 31, and either is or is not fastened thereto, as desired.

While my inventionis not particularly concerned with the details of the pouring spout, I will say that the same may be conveniently constrluted of metal and provided with a suitable lining of refractory material.

In theoperation of my casting machine with the several parts thereof in the positions illustrated in Figs. 1, 2 and 3, the shaft 12 is rotated at a comparatively high speed, and when the rotor and parts carried thereby have reached the proper rate of rotation, molten metal is supplied to the pouring spout 36 and flows into the annular V-shaped channel 23 formed in the inner periphery of the annular core member 19. The metal thus. supplied to the groove or channel 23 is by centrifugal force carried through the sprue openings in the core 19 and against the inner surfaces of the several core o-r plug members 2G and into the several cavitiesy -of the one-piece mold members 25. It is to be understood that by trial it can be determined just howmueh molten metal must be supplied to the channel 23 in order to formfthe num-ber of valves which the machine.' designed to cast, so that there will be practically no excess material left in theI channel 23 after the casting operation has been c ompleted. It will be noted that centrifugal stress exerted upon the molten metal thus forced radially from the V-shaped channel 23 in the several mold cavities is greatest at those points in the several mold cavities in which the valve head and the juncture between the valve head and stem is formed. Thus the resulting casting is of greatest density in the head and at the juncture between the head and stem, which is of course desirable, because these are the parts which are sub` jected to the hardest usage when the finished valve is operated on an engine.

I have found that upon cooling there is a. 115 tendency for the metal constituting the valve stem to pull away from the metal constituting the valve head upon shrinkage due to cooling, this probably -due to the fact that the cross-section of the valve head, being 120 greater than that of the adjacent portion of the stem, the molten metal constituting the stem cools more rapidly than that constituting the head. I have found that theI metal member or nail 27 serves to chill the molten 125 metal at the point where the stem joins the head, and thus overcomes any tendency for separation at this point.

I have found that it is important that the sprues in the core 19 which register with the 130 valve stem cavities in the mold members 25 shall be of less cross-section than the crosssection of the valve stem cavity. When this arrangement is employed, I find that after the casting operation has been completed, and the metal cools, shrinkage of the metal causes the metal in the sprue to separate from stu/th met-al as may remain in the V- shaped channel Q3, thus making it a simple matter to remove each of the valves after the casting operation has been completed, the mold holder structure removed from the rotor, and the fastening devices 20, 20 released. 4

Another decided advantage of the casting machine of my invention is the fact that in the casting operation such impurities as may be in the metal at the time it is poured, or which, being in the mold cavities, may become mixed with the molten metal, are isolated from those parts of the ast valve which are subjected to the roughest usage when the valve is used on an engine. Such impurities are invariably of less density than the metal of which I prefer to cast the valve, with the result that the centrifugal force in the operation of the machine forces the heavy metal to those portions of the mold cavities most distant from the center of rotation, and I find that the lighter impurities have a tendency to settle at some point away from the valve head and the juncture between the head and stem.

In Fig. 7 I have illustrated a casting as it comes from the machine. In order to render the valve capable of use on an engine, the metal member or nail 27 is cut off flush with the upper surface of the valve head, the valve stem is cut to the proper length, and the casting has such finishing operations performed thereon as may be deemed necessary or desirable.

lhile I have described one embodiment of my invention in considerable detail, I do not wish to be limited to the specific arrangement herein shown and described. but claim any eouivalent constructions coming within the terms of the appended claims.

IVhat I claim as my invention is :n

l. A centrifugal casting machine consisting of an annulus comprising a part channeled on its inner surface to receive the molten metal to be cast. a plurality of depressions on tlie outer periphery of said channeled member, sprues affording com munication between said depressions and the inner channel, and a plurality of molds radiating from said annulus, each of said molds having` one end thereof fitted into one of said depressions, means for supporting` said molds, and means for rotating said annulus and parts carried thereby.

2. A casting machine comprising an annu lus, comprising means providing a pouring channel, a plurality of tubular mold holders communication between said channel and said one-piece mold members, and means for-rotating said annulus and mold holders.

3. A valve-casting machine comprising a plurality of radially arranged tubular mold holders, each of said mold holders provided with a one-piece mold having a cavity the surface of which corresponds to the stem and under and lateral surfaces-of the head of a puppet valve, a plug in the outer end of each of said tubular mold holders having its inner surface conformed to correspond to the upper surface of a valve head, means for rotating said mold holders around a common center, and means for sunnlving molten metal to the inner ends of the cavities in said one-piece mold members.

4. A valve-casting machine comprising a plurality of radially arranged tubular mold holders, each of said mold holders provided with a one-piece mold having a cavity the surface of which corresponds to the stem and under and lateral surfaces of the head of a puppet valve, a plug in the outer end of inner surface conformed to correspond to the upper surface of a valve head, each of said. plugs carrying a piece of metal projecting into the mold cavity in the one-piece mold member, and means for supplying molten metal to the inner ends of the cavities in said one-piece mold holders.

In a centrifugal valve-casting nachine, a mold holder radially disposed with respect to its center of rotation, a first mold member within said holder provided with surfaces corresponding to the stem and under and lateral surfaces of the head of a puppet valve therein to be cast, a plug in the outer end 0f the mold holder having its inner surfaces conformed to correspond to the upper surface of the puppet valve head, and means for supplying molten metal to the inner end of the cavity in said first mold member.

6. In a centrifugal valve-casting machine, a mold holder radially disposed with respect to its center of rotation, a first mold member within said holder provided with surfaces corresponding to the stem and under andlateral surfaces of the head of a puppet valve therein to be cast, a plug in the outer end of the mold holder having` its inner surface conformed to correspond to the upper surface of the puppet valve head, a metal shank centrally disposed in said plug projecting into the cavity in said first mold `each of said tubular mold holders having its member, and means 'for supplyingmolten metal to the inner end of said rst mold member.

7. In a machine for casting puppet valves,.

rotatable means providing a mold cavity corresponding in size and shape to a puppet valve therein to be cast, the aXis of the mold cavity being radially disposed With respect to the axis of rotation, the portion of the mold cavity wherein the valve head is to be cast being located farthermost from the axis of rotation, together with means for supplying molten metal to the inner end of said mold cavity.

8. A centrifugal valve-casting machine comprising a rotatable element including a mold member provided with a mold cavity, the Walls of which are conformed to correspond to the stem and under and lateral surfaces of the head of a puppet valve, said mold member disposed with its mold cavity substantially radial to the axis of rotation, and a plug tted against the outer end of said mold member, said plug having its inner surface conformed to correspond to the upper surface of the puppet valve head, to-

gether With means for supplymg molten metal to the inner end of said mold cavity.

9. A centrifugal valve-casting machine comprising a rotatable element including a ,mold member provided with a mold cavity,`

the Walls of which are conformed to correspond to the stem and-under and lateral surfaces of the head of a puppet valve, said mold member disposed With its mold cavity substantially radial to the axis of rotation, and a plug fitted against the outer end of said mold member, said plug having its inner surface conformed to correspond to the upper surface of the puppet Valve head, and metallic means carried by said plug projecting into the mold cavity to chill the molten metal at the junction 0f valve stem and head, together with means for supplying molten metal to the inner end of said mold cavity.

In Witness whereof I hereunto subscribe my name this 18th day of March, 1919.

FREDERICK HILTY. Witnesses:

EDNA V. GUsTAFsoN,

A. G. MCCALEB. 

